zsh 4.2.0 dumping core on completion attempt

[Thorsten Kampe <thorsten@xxxxxxxxxxxxxxxx>]

zsh 4.2.0 dumps core under Cygwin and Linux with these lines in my
.zshrc:

autoload -U compinit; compinit -C   # completion system
# case-insensitive and partial-word then substring
zstyle ':completion:*' matcher-list 'm:{a-zA-Z}={A-Za-z} m:[-._]=[-._] r:|[-./_]=** r:|=*' '+l:|=*'

More precisely it's the "m:[-._]=[-._] r:|[-./_]=**" part.

(These are variations from "6.7 Matching control and controlling where
things are inserted" of the User's Guide)

Surpringly ".f<TAB>" and "_f<TAB>" make zsh dump core while "-f<TAB>"
and "/f<TAB>" do not. The "f" letter can be in fact any *lower case*
letter while "_F<TAB>" or ".H<TAB>" don't make zsh dump core.

Thorsten